The present invention relates to a method for the control of fungus diseases in plants grown in a bed containing peat. The invention further relates to novel Streptomyces griseoviridis strains and their use.
Attempts have been made to control plant diseases in greenhouses by means of disinfection and replacement of the soil and by means of various cultural practices and control by chemicals. So far, biological control has hardly been used as regards plant diseases. However, certain important crops such as lettuce, cucumber and tomato suffer from detrimental soil-spread diseases which have not been possible to control owing to restrictions of use of chemical control agents and hazard periods due to possible residues, or owing to a lack of sufficiently effective products. If some biological control method could be developed for and applied to cultivations of this type, it would be a significant step of progress for both the producer and the consumer.
It is previously known to isolate the antibiotic produced by the actinomycete fungi of the Streptomyces family and to use this antibiotic as a fungistat. However, the action of the antibiotic is short-term, and it ceases when the antibiotic has been consumed.
The object of the present invention is therefore to produce an Streptomyces griseoviridis strain of the Streptomyces family, a strain which thrives in soil and is capable to compete with other micro-organisms in it.